Md. Code, Land Use § 4–206

(a) By local law, a legislative body may specify in a zoning law the allowable modifications that may be made by a variance.

(b) The modifications in a variance:

(1) may be only of density, bulk, dimensional, or area requirements of the zoning law;

(2) may be only allowed where, owing to conditions peculiar to the property and not because of any action taken by the applicant, a literal enforcement of the zoning law would result in unnecessary hardship or practical difficulty as specified in the zoning law; and

(3) may not be contrary to the public interest.